The present invention relates to electrically operated booster rack and pinion steering mechanisms of the kind known in the art as set forth, for example, in International patent number PCT/EP 88/00563.
As disclosed in such prior art, an electric motor drives a rack to operate a steering mechanism. The arrangement provides a safety switch which is normally engaged but which disengages in response to a signal in an electrical control circuit or a redundant safety circuit. However, the signal might be erroneous which could result in malfunctioning of the steering mechanism.